1. Field of the Invention
The present invention relates to a speed control apparatus having a supporting device; a first control member pivotable about the supporting device and retainable in position after pulling a change speed wire to effect a change speed operation, the first control member being returned to a pull starting position after the change speed operation; a second control member pivotable about the supporting device for releasing the change speed wire to effect a change speed operation, the second control member being returned to a release starting position after the change speed operation; a first control portion formed on the first control member; and a second control portion formed on the second control member.
2. Description of the Related Art
A bicycle speed control apparatus as noted above is disclosed in U.S. Pat. No. 5,012,692, for example. This prior control apparatus includes a shift lever acting as the first control member, and a release lever acting as the second control member, which are operable in the same direction to wind and unwind a change speed wire. The shift lever is operated to wind the wire, and the release lever to unwind the wire.
In the above construction, the shift lever returns to home position after each shifting operation. This feature provides the advantage of allowing the shift lever to be operated within an optimal stroke range to facilitate control even when the shift lever is operated to provide a speed many stages away from the home position. That is, the shift lever is shifted back and forth plural times to effect change speed in the wire winding direction. When effecting change speed in the wire unwinding direction, the release lever is operated to cancel action of a position retaining device.
However, since the two levers are operable in the same direction according to the above prior construction, the cyclist could easily operate the wrong lever in a change speed operation. As a result, there is not a little chance of effecting change speed in the wrong direction. Furthermore, this type of speed control apparatus may be disposed adjacent a grip of a handlebar. In such a case, the two levers usually are operated with a thumb. Generally, there is only one position that is optimal for lever operation and, where the two levers are provided, one of the levers tends to be very difficult to operate.